-// Copyright 2006-2007 all rights reserved; see LICENSE file for BSD-style license
-
-package edu.berkeley.sbp;
-import edu.berkeley.sbp.*;
-import edu.berkeley.sbp.util.*;
-import edu.berkeley.sbp.Parser.Table.*;
-import edu.berkeley.sbp.Sequence.Pos;
-import edu.berkeley.sbp.Sequence.Pos;
-import java.io.*;
-import java.util.*;
-import java.lang.reflect.*;
-
-/** a node in the GSS */
-final class Node
- implements Invokable<Pos, Result, Object>,
- IntegerMappable,
- GraphViz.ToGraphViz,
- Iterable<Result> {
-
- /** which GSS.Phase this Node belongs to */
- public GSS.Phase phase() { return phase; }
- public Iterator<Result> iterator() { return results.iterator(); }
- public Parser.Table.State state() { return state; }
-
- public int toInt() { return idx; }
-
- boolean destroyed = false;
-
- public void check() {
- if (destroyed) return;
- boolean dead = true;
- // - all nodes must have a predecessor
- // - non-doomed nodes must either:
- // - be on the frontier or
- // - have a non-doomed node closer to the frontier than themself
- if (phase.isFrontier()) dead = false;
- else for(Result r : successors)
- if (state.doomed) { if (r.usedByAnyNode()) { dead = false; break; } }
- else { if (r.usedByNonDoomedNode()) { dead = false; break; } }
- dead |= results.size()==0;
- if (!dead) return;
- destroyed = true;
- if (phase() != null && phase().hash != null)
- phase().hash.remove(state, predPhase);
- while(successors.size()>0)
- for(Result r : successors) {
- successors.remove(r);
- r.removePred(this);
- break;
- }
- while(results.size()>0)
- for(Result r : results) {
- results.remove(r);
- r.removeSucc(this);
- break;
- }
- results = null;
- successors = null;
- }
-
- //////////////////////////////////////////////////////////////////////
-
- private static int node_idx = 0;
- private final int idx = node_idx++;
-
- private final GSS.Phase phase;
- private final GSS.Phase predPhase;
- private final Parser.Table.State state;
- private boolean fromEmptyReduction;
- private FastSet<Result> results = new FastSet<Result>();
- private FastSet<Result> successors = new FastSet<Result>();
- //private HashSet<Result> results = new HashSet<Result>();
- //private HashSet<Result> successors = new HashSet<Result>();
-
- public final void invoke(Pos r, Result only, Object o) {
- boolean emptyProductions = only==null;
- if (emptyProductions != (r.numPops()==0)) return;
- if (r.numPops()!=0) reduce(r, r.numPops()-1, phase(), only);
- else {
- Input.Region region = phase().getLocation().createRegion(phase().getLocation());
- phase().newNodeFromReduction(r.rewrite(region), r, this);
- }
- }
-
- private void reduce(Pos r, int pos, GSS.Phase target, Result only) {
- for(Result res : results)
- if (only == null || res == only)
- for(Node pred : res.getPreds())
- reduce2(r, pos, target, pred, res.getForest());
- }
-
- void reduce2(Pos r, int pos, GSS.Phase target, Node pred, Forest f) {
- Forest[] holder = r.holder;
- Forest old = pos >= holder.length ? null : holder[pos];
- if (pos < holder.length) holder[pos] = f;
- if (pos>0) pred.reduce(r, pos-1, target, null);
- else {
- Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
- new Reduction(pred, r, r.rewrite(region), target);
- }
- if (pos < holder.length) holder[pos] = old;
- }
-
- Node(GSS.Phase phase, Forest f, Pos reduction, Node pred, State state, boolean fromEmptyReduction) {
- this(phase, new Result(f, reduction, pred), state, fromEmptyReduction);
- }
- Node(GSS.Phase phase, Result pred, State state, boolean fromEmptyReduction) {
- this.phase = phase;
- this.state = state;
- this.fromEmptyReduction = fromEmptyReduction;
- if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
- this.predPhase = pred.phase();
- phase.hash.put(state, pred.phase(), this);
-
- results.add(pred);
- pred.addSucc(this);
- if (!fromEmptyReduction)
- state.invokeReductions(phase().getToken(), this, pred);
-
- state.invokeEpsilonReductions(phase().token, this);
- }
-
- // Add/Remove Successors/Results //////////////////////////////////////////////////////////////////////////////
-
- public void removeSucc(Result succ) {
- successors.remove(succ);
- check();
- }
- public void removeResult(Result result) {
- results.remove(result);
- check();
- }
- public void addSucc(Result succ) {
- successors.add(succ);
- }
- public void addResult(Forest f, Pos reduction, Node pred) {
- for(Result r : results)
- if (r.predecessorsContains(pred)) {
- r.merge(f);
- return;
- }
- Result result = new Result(f, reduction, pred);
- results.add(result);
- result.addSucc(this);
- if (!this.fromEmptyReduction) state.invokeReductions(phase().getToken(), this, result);
- }
-
- // GraphViz //////////////////////////////////////////////////////////////////////////////
-
- public GraphViz.Node toGraphViz(GraphViz gv) {
- if (results.size()==0) return null;
- if (gv.hasNode(this)) return gv.createNode(this);
- GraphViz.Node n = gv.createNode(this);
- n.label = "state["+state.toInt()+"]";
- n.shape = "rectangle";
- boolean haspreds = false;
- for(Result r : results) n.edge(r, "");
- n.color = state.doomed ? "red" : "green";
- ((GraphViz.Group)phase().toGraphViz(gv)).add(n);
- return n;
- }
- public boolean isTransparent() { return false; }
- public boolean isHidden() { return false; }
-
-}